a10_ahci: Correct clock indices for new bindings

r329104 imported 4.15 DTS which brought CCU to a10/a20. In the process, they
swapped the ordering of 'clocks' for allwinner,sun4i-a10-ahci on both
sun4i-a10 and sun7i-a20 from PLL, Gate to Gate, PLL.

Swap it in the driver.